#!/opt/Lua51/bin/lua

-- Created by jiaqiang.ye@lnxall.com
-- Remove duplicated lines in a text file
-- 2025/08/07

package.cpath = "/opt/Lua51/lib/lua/?.so;/opt/Lua51/lib/lua/loadall.so"
package.path = "/opt/Lua51/share/lua/?.lua;/opt/Lua51/share/lua/?/init.lua;/opt/Lua51/lib/lua/?.lua;/opt/Lua51/lib/lua/?/init.lua"

local invoker = require "invoker"
local gfmt = string.format

local function dedup_file(filp)
	local typ, fsize = invoker.statfile(filp)
	if typ == nil then return false end
	if typ ~= "regular" or fsize >= 0x100000 then
		io.stderr:write(gfmt("Error, invalid file type or size: %s\n", filp))
		io.stderr:flush()
		return false
	end

	local fp = io.open(filp, "rb")
	if not fp then
		io.stderr:write(gfmt("Error, failed to open file: %s\n", filp))
		io.stderr:flush()
		return false
	end

	local lines, lmap, nline, dowrite = {}, {}, 0, 0 
	while true do
		local nl = fp:read("*l")
		if nl == nil then break end
		if #nl == 0 then
			dowrite = dowrite + 1
		elseif lmap[nl] then
			dowrite = dowrite + 1
		else
			lmap[nl] = true
			nline = nline + 1
			lines[nline] = nl
		end
	end

	fp:close()
	if dowrite == 0 then return true end
	if nline > 1 then table.sort(lines) end
	io.stdout:write(gfmt("Updating text file: %s ...\n", filp))
	io.stdout:flush()

	fp = io.open(filp, "wb")
	if not fp then
		io.stderr:write(gfmt("Error, failed to open file for writing: %s\n", filp))
		io.stderr:flush()
		return false
	end

	if nline > 1 then
		local wd = table.concat(lines, "\n")
		fp:write(wd)
		fp:write("\n")
	else
		fp:write(lines[1] .. "\n")
	end
	fp:flush()
	fp:close()
	return true
end

os.exit(dedup_file(arg[1]) and 0 or 1)